function s1_hello() {
    echo "hello, world!"
}

function s2_tell_who_i_am() {
    whoami
}

function s3_which_distro_do_i_use() {
    if [ -f /etc/os-release ]; then
	source /etc/os-release
	echo "NAME=\"$NAME\""
    else
	echo "无法确定发行版本"
    fi
}

function s4_view_my_cpu_arch() {
    uname -m
}

function s5_show_first_scsi_disk_size() {
	local bytes=$(lsblk -b -l | grep '^sda ' | awk '{print $4}')
	if [ -n "$bytes" ]; then
		echo $((bytes / 1000 / 1000 / 1000))
	fi
}

function s6_show_main_memory_size_in_megabytes() {
    free -m | grep "Mem:" | awk '{print $2}'
}
